Microsoft currently has three different versions of Windows running on mobile devices. But Microsoft is working to reduce that number, Julie Larson-Green, executive vice president of devices and studios, confirmed in an interview last week.

Speaking at the UBS Global Technology Conference last week, Larson-Greene confirmed Microsoft plans to reduce the number of Windows variants it has in its portfolio. She told attendees during a question and answer session the following:

We have the Windows Phone OS. We have Windows RT and we have full Windows. We're not going to have three. We do think there's a world where there is a more mobile operating system that doesn't have the risks to battery life, or the risks to security. But, it also comes at the cost of flexibility. So we believe in that vision and that direction and we're continuing down that path.

Larson-Greene said Windows RT was Microsoft's "first go" at creating a turnkey, closed system, similar to iOS for the iPad. Like iOS, Windows RT isn't as flexible, she acknowledged, but it's more seamless and simplified.

"I think we didn't differentiate the devices [Surface RT vs. Surface Pro] well enough. They looked similar. Using them is similar. It just didn't do everything that you expected Windows to do. So there's been a lot of talk about it should have been a rebranding. We should not have called it Windows. How should we have made it more differentiated? I think over time you'll see us continue to differentiate it more," she said.

As I noted back in October, Microsoft seems to be thinking about creating some kind of hybrid OS that will bring closer together Windows RT and the Windows Phone OS. And at least according to one of my sources, it's more likely that the Windows Phone OS core is what Microsoft will use as the starting point, rather than Windows RT. If Microsoft is pursuing this path, there might just be full Windows and the new hybrid ARM-targeted variant of Windows in just over a year.

Larson-Green dropped a couple of other interesting tidbits during her UBS interview on November 21. She hinted that Microsoft is working towards a future where users may carry multiple kinds of phones or portable devices of some kind. She said that there could be a time when users have "three or four" phone-like devices they'll be able to switch between, using the one best suited to a particular scenario.

"I have that six-inch one [presumably the Nokia 1520 or a device like it]," she said, "and when you're traveling on the train and you're using public transit so you can see more and do more, and then when you're out in the evening and you only have your suit, or your evening dress, you have a small one that slips in your pocket. You can buy more than one."